Problem: The Digidesign C|24 in studio 6 was occasionally turning off without any human intervention. This would cause the speakers to bark when the power was restored to the C|24.
Solution: The power cable on the C|24 power supply did not have a solid connection. If the cable moved just slightly, it would disconnect the hot side and interrupt the connection. It seems that the AC pins are not as long or the connector is too deep for most of our standard power cables. I found one that fit tighly in the connector and the problem dissipated.
For the record, the C|24 was fine. The problem was from a power cable.